National Weather Service forecasts for San Francisco project a daytime high near 68°F on May 16 under mostly sunny conditions with moderate onshore westerly winds, supporting the market's leading 64-65°F outcome at 44% implied probability. Persistent Pacific marine layer influence and coastal advection typically cap May highs near the 67°F climatological average by limiting afternoon warming, though recent high-pressure building has favored greater stratus burn-off in model runs. This setup positions 66-67°F (27%) as a plausible secondary outcome if winds remain lighter than expected, while cooler 62-63°F (21%) scenarios hinge on thicker low clouds persisting through peak heating hours. Hourly NWS guidance and real-time airport observations at KSFO will drive final resolution as marine influences evolve overnight.